1. Field of Invention
This invention relates to polymeric materials typically used in oilfield applications and environments and, more particularly, to systems and techniques utilizing swellable polymeric materials in downhole environments to seal least a portion of a wellbore.
2. Discussion of Related Art
Bosma, et al., in International Application Publication No. WO 2003/008756, disclose a wellbore system comprising borehole extending into an earth formation, a tubular element extending into the borehole. A cylindrical wall surrounds the tubular element such that annular space is formed between the tubular element and the cylindrical wall. At least one seal member is in the annular space and is movable between a retracted mode such that the seal member has a first volume and an expanded mode in which the seal member has a second volume that is larger than the first volume. In the expanded mode, the seal member seals the annular space. The seal member includes a material that swells upon contact with a selected fluid.
Vercamer, et al., in U.S. Pat. No. 6,820,690, disclose a technique for the use of a variety of completion elements in a wellbore environment. The technique involves an insertion guide disposed within an open hole section of a wellbore. The insertion guide may be radially expanded towards the surrounding formation to remove excess annular space.
Richard, et al., in U.S. Pat. No. 6,848,505, disclose a method of sealing casing or liners in a wellbore. Stands of casing or liner receive a jacket bonded to an outer surface. The jacket is a rubber compound bonded to the outer wall. The rubber formulation responds to well fluids by swelling at a predetermined rate. The casing or liner can also be expanded with a swage prior to the onset of significant jacket swelling.
Patel, et al., in U.S. Patent Application Publication No. 2005/0199401, disclose a sealing system used seal an exterior surface of a casing or open wellbore. The sealing system includes a swellable material that swells from an unexpanded state to an expanded state thereby creating a seal when the swellable material comes in contact with a triggering fluid.
Bosma, et al., in International Application Publication No. WO 2005/012686, disclose a system for sealing a space in a wellbore formed in an earth formation. The system includes a swellable body arranged in the wellbore to seal the space upon swelling of the swellable body. The swellable body is susceptible to formation water flowing into the wellbore. The swellable body includes a matrix material with a compound soluble in the formation water. The matrix material substantially prevents or restricts migration of the compound out of the swellable body and allows migration of the formation water into the swellable body by osmosis.
Nguyen, in U.S. Pat. No. 6,935,432, disclose an apparatus and method of utilizing an expandable media assembly to create an annular barrier in a subterranean well. The apparatus has a tubing assembly placed in the wellbore such that an annular space is formed between an outer surface of the tubing assembly and the wellbore. The apparatus has an expandable media assembly having an expandable material which is initially in a run-in position and is capable of increasing in volume to a set position in the wellbore thereby creating an annular barrier blocking fluid flow along the annular space. The expandable material can be a foam, gel, or alloy. The media can be deformable upon enlargement and conform to the wellbore wall. The media can be a sleeve secured to the tubular assembly or a medium carried in a pressurized canister for release at a selected downhole location. The media can be thermally, chemically, or otherwise activated to expand and can be used in conjunction with radially expandable screen assemblies and tubing assemblies.
Freyer, in European Patent Specification No. EP 1 315 883, disclose a well packing for sealing an annular space between a well wall and a production tubing, comprising an expandable element mainly consisting of rubber material. The packer has a first elastomer adapted to swell when exposed to hydrocarbons, and a second elastomer disposed externally to the first elastomer.
The above listed references fail to provide a readily deployable seal requiring minimal actuation to effect a seal in a wellbore. Furthermore, the above listed references fail to address the control of the mechanical properties and swelling kinetics through the use of a polymeric material. Accordingly, it is an object of the present invention to addresses these limitations of the prior art through the polymeric seal recited herein.